1. Field of the Invention
The present invention relates to a light communication system, having a high transmission rate.
2. Description of the Prior Art
In the past, when digital signals "1" and "0" are light-transmitted, a light pulse at a predetermined frequency is sent for the signal "0", for example, and the light pulse is not sent for the signal "1". That is, a 100% modulation AM-modulation system is employed.
In such a system, a filter circuit which passes only a carrier frequency is used in a receiver to eliminate unnecessary light signals. However, since the filter circuit usually produces a gradually decaying output signal even after an input signal has disappeared, due to self-resonance, an apparent input signal period is longer than an actual input signal period. Accordingly, signals "1" and "0" which do not allow neglect of this delay time cannot be processed in this system. This restricts the rate of data transmission.